sugary jelly-filled donuts, and then there are the ones that

含糖果凍的甜甜圈，然後有那些

are really bad for your health.

是真的對你的健康不利。

These ones.

這些人。

Well, I can see why people pay money to watch this.

好吧，我知道為什麼人們花錢看這個了。

But take any friction fighting hijinks to the roads

但是，把任何摩擦戰鬥的嬉戲帶到路上去吧

and it's a serious hazard for motorists and for trees.

而且對駕車者和樹木都有嚴重的危害。

They were okay, but extremely lucky.

他們還好，但極其幸運。

So you should never attempt this.

所以你千萬不要嘗試這樣做。

But off the road, and in the hands of an expert,

但在路外，而且是在專家手中。

donuts are a masterclass in static and kinetic friction.

甜甜圈是靜摩擦和動摩擦的大師級作品。

Our driver hits the gas hard and turns sharply.

我們的司機猛踩油門，急轉彎。

The excessive torque at the rear wheels

後輪扭矩過大

overcome static friction between the tires and the ground,

克服輪胎與地面之間的靜摩擦。

so they become subject to kinetic friction,

所以它們會受到動摩擦力的影響。

which offers less resistance.

它的阻力較小。

The reduced grip allows centrifugal force

握力減小，可獲得離心力。

to slide the wheels in a circular path,

以使輪子在圓形路徑上滑動。

like the ring of a donut.

像甜甜圈的環。

So not just risky, but scientifically

所以，不僅風險大，而且科學上的

tricky to pull off, although not everyone seems to think so.

雖然不是每個人都這麼認為，但要做到這一點還是很棘手的。

I mean this guy thinks he's got the science down,

我的意思是，這傢伙認為他的科學下來。

but in fact he hasn't lost traction at his back tires

但事實上，他的後胎並沒有失去牽引力。

at all.

完全沒有。

He's just using rollers, see, which does reduce the risk

他只是用了滾輪，看，這確實減少了風險。

of kinetic friction, burning up the tires,

的動摩擦力，燒燬輪胎。

but doesn't make it less dangerous.

但並不代表它就不危險了。

CAMERA MAN: Woah!

哇！

Watch out, man!

小心，夥計！

BEN AARON: It's a bit late for that.

Ben AARON：現在說這個有點晚了。

Ah, the parking lot donut, using kinetic friction

啊，停車場的甜甜圈，使用動能摩擦力

and centrifugal force to drift into a space, like a glove.

和離心力的作用下，像手套一樣飄進一個空間。

Having successfully turned static friction

成功地將靜摩擦力轉變成

to kinetic at the rear wheels, he then

在後輪的動能上，他再

momentarily let up the power on those wheels

剎那間發力

and went back to static.

並回到了靜態。

So, he stopped circling, and went straight.

於是，他不再繞圈子，而是直奔主題。

There are better ways to park a car.

有更好的方法來停放汽車。